1. Field of the Invention
The present invention relates to a liquid chromatograph including an HPLC (high-performance liquid chromatograph), and also relates to an analytical device including, as a part thereof, a liquid chromatograph, such as an LCMS (liquid chromatograph mass spectrometer).
2. Description of the Related Art
In a liquid chromatograph, in order to switch between and send several types of mobile phases to an analysis channel, a channel switching valve is connected to a delivery pump, and switching among several mobile phases is enabled with respect to one delivery pump (see JP 2002-277451 A).
Channel switching valves are referred to as a first-stage channel switching valve, a second-stage channel switching valve, etc. in the order from the one closest to the pump (on the downstream side). Whereas the first-stage channel switching valve is provided to the liquid chromatograph as pre-installed equipment, the second-stage channel switching valve is an optional channel switching valve that is connected by a user to one of the ports of the first-stage channel switching valve. It is also possible to connect third- and later-stage channel switching valves, and these are also optional channel switching valves.
According to such a delivery system, the total delivery amount of mobile phases and the remaining amount of mobile phases are calculated by the following method.    (1) The type (the number of ports) and connection/non-connection of the first-stage channel switching valve are set to a channel control section. Since the first-stage channel switching valve is a pre-installed structural element, some channel control sections are enabled to automatically recognize the type and connection/non-connection of the first-stage channel switching valve. However, with respect to the optional second- and later-stage channel switching valves, setting of the types and connection/non-connection thereof is not performed.    (2) The total amount of mobile phase is set for the mobile phase connected to each mobile phase channel.    (3) A delivery control section calculates the total delivery amount of each channel connected to the first-stage channel switching valve based on the delivery flow rate of the pump and the open time of each port of the first-stage channel switching valve.    (4) The total delivery amount is subtracted from the total amount of mobile phase, and the remaining amount of mobile phase of each channel connected to the first-stage channel switching valve is determined.
With a conventional liquid chromatograph, even when the second- and later-stage channel switching valves are connected, only the total delivery amount of each channel connected to the first-stage channel switching valve may be calculated, and it is not possible to determine the total delivery amount of each mobile phase connected to the port of the second- or later-stage channel switching valve.